“Oh, I think you are intelligent people. You will vote the right way,” says Markus Miele, one of the company’s two co-proprietors.

“As long as you don’t have a referendum on whether people want to buy German washing machines, I think we’ll be able to sell our products there.”

His co-proprietor, Reinhard Zinkann, agrees, noting that Miele already exported to Britain before it entered the EU.

"You will vote the right way... As long as you don’t have a referendum on buying German washing machines"

Markus Miele

“We were successful before that and we will probably be successful afterwards as well, as there will always be demand for a premium brand. So I am not afraid for us,” he says.

Miele is a very German company. Nearly two-thirds of its workforce is still in Gutersloh, the North Rhine-Westfalia city where it was formed in 1899 after Carl Miele and Reinhard Zinkann, the great-grandfathers of today’s co-proprietors, met by chance in a bar.

Germany accounts for 30pc of Miele’s €3.49bn (£2.56bn) sales and most of its production – it makes 850,000 washing machines a year. The company is a proud member of the “Mittelstand” community of privately-owned businesses, though it now also has factories in the Czech Republic and Romania. Britain is Miele’s fifth biggest market after Germany, the US, Switzerland and Australia, and home to 500 of the company’s 17,750 employees.

Miele has a “customer experience” centre in Abingdon, Oxfordshire, and “galleries” in London to show customers how to use its products.

“The UK is a very interesting market for us,” says Miele. “It’s growing at a double-digit percentage rate for us because we’ve found the right way to go to that market.

“We’ve invested a lot there in logistics, warehousing and the customer experience centre and we have a long history there, so people know the brand and how durable the machines are.”

Miele has a customer experience centre in Oxfordshire Photo: Miele

Miele, which tests its machines to last 20 years, prides itself on a culture of continuous improvement dating back to when its co-founders wrote “immer besser” (forever better) on their first butter churn.

All the company’s 70 managing directors, including Miele and Zinkann, are the founders’ descendants and the co-proprietors say Miele’s family ownership means they can take a long-term view.

For example, Miele has its own sales and service subsidiaries in 47 countries, but sells through importers and distributors in another 50 nations where it doesn’t think it can make a long-term return from its own operations.

With the weak euro helping to decrease prices of its appliances outside the eurozone, Miele achieved sales growth of 8.3pc in the 12 months to the end of June, its highest annual growth since 2005. Excluding exchange rate effects, sales grew by 6.4pc.

“When you have a lot of your manufacturing in the eurozone and particularly in Germany, you always have to look for improvements because you have to charge a higher price,” he says.

Miele’s products are more expensive than the budget end of the white goods market, yet its co-proprietor remains sanguine.

“It’s like what happens in the car market,” says Miele. “There are entry- level cars and premium cars and sometimes these are more than a few hundred per cent more expensive than the entry-level cars.

“Yes, our customers spend a little more on washing machines, but they also get more. I received a letter from an elderly lady in East Germany who said she was too poor to buy a different brand.

“She had used her Miele washing machine for more than 30 years and worked out it was the cheapest washing machine she had ever bought.” Zinkann feels this is a common occurrence. “If your product breaks down after five or six years, the cost of the service call is nearly coming to the cost of the machine, so you’re paying for it a second time.

“If you have a Miele machine, this can’t happen or shouldn’t happen. Even if something happens, our service technician can update the machine to the latest standard, which gives you the feeling of having a new product,” he says.

Miele believes the company's premium positioning made it more resilient to the global financial crisis than peers, with sales declining by only 1.2pc in 2008-09 before returning to growth the following year.

"The Mittelstand is not necessary for people to buy patriotically. It’s that people want to buy good products"

“It’s not necessary for people to buy patriotically. It’s that people want to buy good products,” he insists. “The Mittelstand is quite a diverse group but what’s really important for the Mittelstand companies is that they take their own decisions.”

“It comprises a lot of companies from big to small and there are many ideas behind it. Our apprentice systems starts when people are still at school. And the Mittelstand has a lot of family-owned companies who look to the long term. Britain can have one, but it takes a lot of different actions and it’s not only one switch that you can just flick and then the Mittelstand is there. It takes time to grow.”

For Miele, the co-proprietors say the key is being completely self-financed and not having external shareholders.

“We like to invest if we see the long- term revenue,” says Miele. “We don’t have to see revenue for next year. It can be in three or even five years.

“But we’re going to refrain from investing if we don’t think there’s a return over seven years or 10 years.

“It’s just the two families. We fund all the investment ourselves. We want to grow organically. It’s like a human body cell. If it grows too fast, that’s not good. That’s cancer. If it grows too slowly, that’s also not good. But there has to be growth always.”

Will Miele ever float? Its co-proprietors don’t think so. “The family members like what we do,” says Miele.

“They’re happy with the company and the revenues. As long as they’re happy with what we’re doing and the results, the company can have a strong future.”

“We’ve never been on the stock market,” adds Zinkann. “We see competitive advantage in our independence. Our independence is our strength. We’re able to think in generations. It’s only possible because we’re independent and auto-financed. Yes, of course you can grow faster with equity from the stock market or wherever, but we think we can only grow healthily and sustainably by thinking long-term.